The present invention relates generally to image forming devices, and in particular to a dual sliding shutter system for adding toner to an image forming machine.
Toner is a dry, powdered form of ink applied to media sheets in electrophotographic image forming devices. Toner is a consumable item, which must be replenished periodically. Pouring toner from a bottle into a toner reservoir in the image forming device is a notoriously messy operation, often staining a user's hands and clothes with toner, resulting in user dissatisfaction.
Cartridges that contain toner and are inserted as a unit into the image forming device to replenish its toner supply are known in the art. Typically, a toner cartridge is inserted using one motion, e.g., sliding the cartridge into place, and an integral door or shutter is opened using a different motion, e.g., twisting the cartridge about its axis, to open a passageway for toner to flow from the cartridge into a developer unit in the image forming device. These cartridges are difficult for inexperienced users to properly install, resulting in cartridges that are improperly inserted, inserted but not twisted properly such that the toner does not flow from the cartridge or only partially flows, and the like.
In another type of toner cartridge known in the art, shutters on the toner cartridge and/or the developer are held in a closed position by springs. When the toner cartridge is inserted into an image forming device, the shutters are opened, allowing toner to flow. Upon removal of the cartridge, the springs move the shutters to the closed positions. In these cartridges, the spring forces must be overcome upon inserting the cartridge. That is, the spring forces oppose the insertion of the cartridge into the image forming device, increasing the required insertion force. Additionally, the springs add cost and complexity to cartridge design.